Influence of the Ground Reaction Force Prediction on the Human Structure Interaction Phenomenon: An Application of a Bipedal Model

Vibration serviceability has been widely discussed in the last decades since the changes in the features of contemporary structures led to their susceptibility to vibrate excessively, even due to usual human-induced loads, such as walking. Despite that, guidelines and standards still neglect the intrinsic interaction between pedestrians and structures. Therefore, models considering such interaction require a more profound understanding and experimental validation to be a reliable mathematical framework for practical design applications. The present study investigates a biodynamic single degree-of-freedom bipedal model (BM) performance against experimental data obtained from two lively footbridges. The measured filtered accelerations from a single-pedestrian crossing in resonance with the first vertical vibration mode are used as a reference. An interaction formulation is applied for this matter, and the influence of the bipedal nature of walk simulation and ground reaction forces (GRFs) predictions were analysed. There was evidence that BM overestimated the GRF and that is perceivable through the values of the dynamic load factors (DLFs) employed to characterize such forces. For the case where vibration levels were more prominent, the reciprocal effects due to the human-structure interaction resulted in remarkable amplifications for the applied forces and structure’s response, featuring significant differences from the experimental results. The model simplifications likely led to this overestimation. However, only additional investigations against experimental data measured at the pedestrian body in varied vibration levels can confirm this since perceivable vibrations can interfere with the walking pattern.